空对象的判断

jq

1、$.isEmptyObject(object)

var obj={};
console.log($.isEmptyObject(obj));//true

var parent={age:18};
var son=Object.create(parent);
console.log($.isEmptyObject(son));//false

js

2、JSON.stringify(object)

var obj={};
console.log(JSON.stringify(obj)=="{}");//true

3、for循环

var obj={age:18};
var nullObj={};
var objectIsNull=function(obj){
    for(var key in obj){
        return false;
    }
    return true;
}
console.log(objectIsNull(obj));//false
console.log(objectIsNull(nullObj));//true

4、Object.getOwnPropertyNames(object)

var obj={age:18};
var objKeys=Object.getOwnPropertyNames(obj);
console.log(objKeys.length==0);//false

var nullObj={};
var objKeys=Object.getOwnPropertyNames(nullObj);
console.log(objKeys.length==0);//true

5、Object.keys(object)

var obj={age:18};
var objKeys=Object.keys(obj);
console.log(objKeys.length==0);//false

var nullObj={};
var objKeys=Object.keys(nullObj);
console.log(objKeys.length==0);//true